Method and device for quality controlling packets

ABSTRACT

A method and device for quality controlling packets of cigarettes, whereby, as a packet is fed, in use, through a quality control station, an optical detecting unit acquires data relative to given portions of the packet, which portions are coated with material optically detectable at wavelengths outside the visible range; the data detected by the optical detecting unit is compared with reference data, and the outcome of the comparison is used to determine acceptance or rejection of the packet; in this way, the condition of the packet can be determined regardless of the graphics on the packet.

The present invention relates to a method and device for qualitycontrolling a packet; to a packet; and to a relative blank.

The present invention may be used to advantage in packing cigarettes, towhich the following description refers purely by way of example.

BACKGROUND OF THE INVENTION

Packets produced on a packing machine are normally quality controlled todetermine any defects, in particular, stains, scratches, or dents; andany faulty packets are subsequently rejected.

In U.S. Pat. No. 4,912,554, a packet is fed along a path through aquality control station where television cameras acquire an image of thepacket; and the image is compared with a reference image to determinewhether or not the packet is to be rejected.

Though efficient, the known quality control system described above hasbeen found to fall short in some respects in terms of versatility andsensitivity. In particular, whenever changes are made to the graphics(artwork, brands, and/or colours) on the outside of the packets (e.g.so-called “brand changes”), changes must also be made to the referenceimage. Moreover, in areas of the packet bearing complex and/or highlycoloured images, defects such as scratches or dents are especiallydifficult to detect. In other words, the artwork and colours on thepacket act as noise during detection.

U.S. Pat. No. 5,877,506 discloses a device, which is designed to monitorblanks and comprises a source of infrared radiation. Such a device isdesigned to monitor only the contours of the blanks in order to verifythe supply of the correct blanks, when there is a change in the type ofpackaging to be manufactured, and the correct positioning of the blanks.The device disclosed in U.S. Pat. No. 5,877,506 is not designed tocontrol the quality of the blanks and is not designed to monitorsurfaces of the blanks.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method and devicefor quality controlling a packet, designed to eliminate, at leastpartially, the aforementioned drawbacks, and which at the same time arecheap and easy to implement.

According to the present invention, there is provided a method ofquality controlling a packet; the method comprising a feed step to feedthe packet along a feed path through a quality control station; anoptical detecting step to detect at least one detected data itemrelative to at least one given portion of the packet; and a comparingstep to compare the detected data item with at least one reference dataitem to determine rejection or acceptance of the packet; the methodbeing characterized in that the given portion comprises at least apigment, which is optically detectable at at least one given wavelengthoutside the visible range; the detected data item being detected byreceiving electromagnetic radiation having said given wavelength fromsaid pigment.

According to the present invention, there is also provided a device forquality controlling a packet; the device comprising at least one opticaldetector for optically detecting at least one data item relative to atleast one given portion of the packet; and a comparing unit forcomparing the detected data item with at least one reference data itemto determine rejection or acceptance of the packet; the device beingcharacterized in that the optical detector is designed to detect thedetected data item by receiving electromagnetic radiation, which, inuse, comes from at least a pigment of the given portion and has at leastone given wavelength outside the visible range; the comparing unit beingdesigned to elaborate said detected data item relating to saidelectromagnetic radiation coming from the pigment.

According to the present invention, there is also provided a packethaving at least one given portion optically detectable at at least onegiven wavelength outside the visible range; the given portion comprisingat least one first line, and at least one second line crosswise to thefirst line; the first and second line extending at least from a firstedge to a second edge of the packet.

BRIEF DESCRIPTION OF THE DRAWINGS

A number of non-limiting embodiments of the present invention will bedescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 shows a view in perspective, with parts removed for clarity, of adevice for quality controlling packets in accordance with the presentinvention;

FIG. 2 shows a larger-scale section along line II-II of the FIG. 1device;

FIG. 3 shows a front view in perspective of a packet of cigarettes inaccordance with the present invention;

FIG. 4 shows a spread-out view of a blank by which to form the FIG. 3packet;

FIGS. 5 to 9 show front views in perspective of alternative embodimentsof packets in accordance with the present invention;

FIGS. 10 to 14 show spread-out views of blanks by which to form the FIG.5 to 9 packets respectively;

FIG. 15 shows a portion of the FIG. 3 packet and the correspondingresponse of a detecting device;

FIG. 16 shows a front view in perspective of a damaged FIG. 3 packet.

DETAILED DESCRIPTION OF THE INVENTION

Number 1 in FIG. 1 indicates as a whole a device for quality controllinga “rigid” packet 2 of cigarettes (FIG. 3). Packet 2 comprises acup-shaped body 3, and a lid 4 hinged to cup-shaped body 3. Cup-shapedbody 3 comprises a front wall 5, two lateral walls 6 (only one shown inFIG. 3), a bottom wall (now shown), and a rear wall (not shown). Lid 4comprises a front wall 5 a, two lateral walls 6 a (only one shown inFIG. 3), a top wall 7, and a rear wall (not shown). Lateral walls 6 and6 a are connected to respective front walls 5 and 5 a and to therespective rear walls (not shown) by relative longitudinal edges 8.Front wall 5 a and the rear wall (not shown) of lid 4 are connected totop wall 7 by relative edges 9; and front wall 5 is connected to thebottom wall (not shown) by an edge 10.

Packet 2 is formed from a substantially flat blank 11 (FIG. 4)comprising a central portion 12, and a number of lateral panels 13located symmetrically on opposite sides of portion 12. Portion 12comprises a number of panels aligned lengthwise of blank 11; each panel13 is connected to portion 12 by a preformed fold line 14; and, oncefolded, fold lines 14 correspond to edges 8 of packet 2.

Blank 11 has a grid 15 comprising a number of parallel longitudinallines 16, and a number of parallel lines 17 crosswise, in particular,perpendicular, to lines 16. Lines 16 and 17 are invisible to the nakedeye, and comprise special pigments detectable optically at a givenwavelength outside the visible range, in particular at a wavelength inthe ultraviolet range.

Device 1 (FIG. 1) comprises a transfer unit 18 for feeding packet 2along a path P through two quality control stations 19 and 20. Device 1also comprises two conveyors 21 and 22, each having a suction belt 23positioned on edge and looped about two vertical-axis pulleys 24.Conveyor 21 receives packet 2 from an input station 25, and feeds packet2 through quality control station 19 to conveyor 22; and conveyor 22feeds packet 2 through quality control station 20 to an output station26.

Two detecting units 27 and 28 are located at quality control stations 19and 20 respectively, and each comprise an optical detector 29, 30, andan electromagnetic radiation source 31. Optical detectors 29 and 30acquire data relative to grid 15 by receiving electromagnetic radiationat said given wavelength.

As shown more clearly in FIG. 2, two inclined mirrors 32 are located onopposite sides of conveyor 21 at quality control station 19, to enableoptical detector 29 to analyze lateral walls 6 and 6 a of packet 2.

Device 1 also comprises a central control unit 33 which receives thedata acquired by detecting units 27 and 28, and in turn comprises acomparing unit 34 for comparing the acquired data with reference data.On the basis of the comparison between the acquired and reference data,central control unit 33 activates a known reject device 35 (shownschematically in FIG. 1) located immediately downstream from device 1and for eliminating any faulty packets downstream from conveyor 22.

In actual use, when packet 2 is located at quality control stations 19and 20, sources 31 emit electromagnetic radiation to bring the pigmentsto an excited state, decaying from which the pigments themselves emitelectromagnetic radiation at said given wavelength outside the visiblerange. At this point, optical detectors 29 and 30 detect the shapeand/or position of various areas of grid 15 and/or the intensity of theelectromagnetic radiation, at the given wavelength, from the areas ofgrid 15.

The electromagnetic radiation emitted by sources 31 and theaforementioned pigments may have different wavelengths. In the case theelectromagnetic radiation emitted by sources 31 and the aforementionedpigments have indeed different wavelengths, as optical detectors 29 and30 detects electromagnetic radiation at the aforementioned givenwavelength, noise due to, for example, radiation simply reflected bypacket 2 is disregarded; as a consequence, the detection of data is moreprecise.

The detected shape, position, and/or intensity are compared by comparingunit 34 with a reference shape, position, and/or intensity; and, in theevent the difference between the detected and reference data exceedsgiven threshold values, central control unit 33 activates reject device35.

In connection with the above, it should be pointed out that, in theevent packet 2 is dented, the shape and position of detected areas ofgrid 15 differ from the reference shape and position of packet 2 inperfect condition; and, in the event packet 2 is scratched, theintensity of the electromagnetic radiation, at the given wavelength, ofthe scratched area of grid 15 is below the reference intensity. FIG. 16shows the FIG. 3 packet 2 with a dent along edge 10, and the relativedistorted grid 15.

Optical detectors 29 and 30 preferably each comprise known area scalesfor detecting electromagnetic radiation, at the given wavelength, alongscan lines 36. By way of example, FIG. 15 shows an area of grid 15, andthe corresponding area scale response along scan line 36. The y axisshows the position along the scan line, and the x axis the intensity ofthe relative pixels. In this case, the comparing unit compares thepositions, heights, and/or shapes of the peaks in FIG. 15 with referencepositions, heights, and/or shapes.

Device 1 as described above allows changes to be made to the graphics(artwork, brands, and/or colours) on the outside of packet 2 (e.g.so-called “brand changes”) without changing the reference data, and alsoprovides for accurately determining the condition of packet 2, even inareas of packet 2 bearing complex and/or highly coloured images.

In this connection, it should be pointed out that, since opticaldetectors 29 and 30 only detect electromagnetic radiation at said givenwavelength outside the visible range, whatever is picked up by opticaldetectors 29 and 30 is unaffected by the graphics on the outside ofpacket 2.

FIGS. 5 to 14 show alternative embodiments of packet 2 and relativeblank 11. As can be seen, packets 2 in FIGS. 5 to 9 are substantiallysimilar to packet 2 described above, except that grid 15 is replaced byone or more given portions 37 of various forms and comprising saidpigments.

Grid 15 is preferably stamped on blank 11 off the packing machine, i.e.at the packing material manufacturer's plant or paper mill.Alternatively, the grid may be stamped on the blank by means of astamping device upstream from the packing machine.

The FIG. 5 packet 2, formed from the FIG. 10 blank, comprises oneportion 37 on lateral wall 6 a of lid 4. In this case, in the event thelateral panel 13 partly defining wall 6 a is not glued properly and istherefore partly raised, optical detector 29 can detect portion 37directly, and not only by means of one of mirrors 32. In FIGS. 5 and 10,portion 37 is hatched.

In the FIG. 6 packet 2, formed from the FIG. 11 blank 11, portion 37extends along the edges of packet 2. As shown in FIG. 11, portion 37extends at least partly along the edge of blank 11. In FIGS. 6 and 11,portion 37 is hatched.

In the FIG. 8 packet 2, formed from the FIG. 13 blank 11, portion 37comprises two substantially perpendicular lines on front wall 5, oneextending from one longitudinal edge 8 to the other longitudinal edge 8,and the other extending from edge 9 to edge 10. In FIGS. 8 and 13,portion 37 is shown by bold lines.

In the FIG. 7 packet 2, formed from the FIG. 12 blank 11, portion 37comprises two substantially perpendicular lines, a first extending onfront wall 5, lateral walls 6, and the rear wall (not shown in FIG. 7)of cup-shaped body 3, and a second extending on front walls 5 and 5 a,on the bottom and rear walls (not shown in FIG. 7) of cup-shaped body 3,and on top wall 7 and the rear wall (not shown in FIG. 7) of lid 4. InFIGS. 7 and 12, portion 37 is shown by bold lines.

The FIG. 9 packet 2, formed from the FIG. 14 blank 11, has a portion 37comprising a number of lines, which extend along the edges of packet 2,and which, from the corners, intersect on each wall 5, 5 a, 6, 6 a, 7,each of the rear walls (not shown), and the bottom wall (not shown). InFIGS. 9 and 14, portion 37 is shown by bold lines.

Though the above description and accompanying drawings relate to aconventional hinged-lid packet of cigarettes, the teachings of thepresent invention obviously also apply to packets of cigarettes of anytype, such as a hinged-lid packet with rounded or bevelled edges, or a“soft” packet of cigarettes. The teachings of the present inventionobviously also apply to cartons of packets of cigarettes, and to packetsof other than cigarettes, such as packets of food products,confectionary, or toiletries.

1) A method of quality controlling a packet; the method comprising afeed step to feed the packet (2) along a feed path (P) through a qualitycontrol station (19; 20); an optical detecting step to detect at leastone detected data item relative to at least one given portion (15; 37)of the packet (2); and a comparing step to compare the detected dataitem with at least one reference data item to determine rejection oracceptance of the packet (2); the method being characterized in that thegiven portion (15; 37) comprises at least a pigment, which is opticallydetectable at at least one given wavelength outside the visible range;the detected data item being detected by receiving electromagneticradiation having said given wavelength from said pigment. 2) A method asclaimed in claim 1, wherein the position of said given portion (15; 37)is detected at said detecting step; the detected position being comparedwith a reference position at said comparing step. 3) A method as claimedin claim 1, wherein the intensity of the electromagnetic radiation, atsaid given wavelength, from the given portion (15; 37) is detected atsaid detecting step; the detected intensity being compared with areference intensity at said comparing step. 4) A method as claimed inclaim 1, wherein the shape of said given portion (15; 37) is detected atsaid detecting step; the detected shape being compared with a referenceshape at said comparing step. 5) A method as claimed in claim 1, whereinthe given portion (15; 37) comprises at least one first line and atleast one second line crosswise to the first line; the first and secondline extending at least from a first edge (8; 9) to a second edge (8;10) of the packet (2). 6) A method as claimed in claim 1, wherein thegiven portion (15; 37) comprises at least one first line .(16), and atleast one second line (17) crosswise to the first line (16); the firstline (16) extending from a first edge (9) to a second edge (10) of thepacket, and the second line (17) extending from a third edge (8) to afourth edge (8) of the packet (2). 7) A method as claimed in claim 1,wherein the given portion (15; 37) comprises a grid (15) having a firstnumber of lines (16) parallel to one another, and a second number oflines (17) parallel to one another and crosswise to the first number oflines (16). 8) A method as claimed in claim 1, wherein the given portion(15; 37) extends at least partly along at least one edge of the packet(2). 9) A method as claimed in claim 1, wherein the packet (2) is formedfrom a blank (11); the given portion (15; 37) extending at least partlyalong at least part of the edge of the blank (11). 10) A method asclaimed in claim 1, wherein said given wavelength is a wavelength in theultraviolet range. 11) A method as claimed in claim 1, and comprising anirradiating step to irradiate said given portion (15; 37); and anemitting step, at which the pigment emits electromagnetic radiation atsaid given wavelength. 12) A method as claimed in claim 11, wherein,during the irradiating step, said given portion is irradiated withelectromagnetic radiation having a wavelength different from said givenwavelength. 13) A device for quality controlling a packet; the devicecomprising at least one optical detector (29; 30) for opticallydetecting at least one data item relative to at least one given portion(15; 37) of the packet (2); and a comparing unit (34) for comparing thedetected data item with at least one reference data item to determinerejection or acceptance of the packet (2); the device beingcharacterized in that the optical detector (29; 30) is designed todetect the detected data item by receiving electromagnetic radiation,which, in use, comes from at least a pigment of the given portion andhas at least one given wavelength outside the visible range; thecomparing unit being designed to elaborate said detected data itemrelating to said electromagnetic radiation coming from the pigment. 14)A device as claimed in claim 13, wherein the optical detector (29; 30)detects the position of said given portion (15; 37); the comparing unit(34) comparing the detected position with a reference position. 15) Adevice as claimed in claim 13, wherein the optical detector (29; 30)detects the intensity of the electromagnetic radiation, at said givenwavelength, from the given portion (15; 37); the comparing unit (34)comparing the detected intensity with a reference intensity. 16) Adevice as claimed in claim 13, wherein the optical detector (29; 30)detects the shape of said given portion (15; 37); the comparing unit(34) comparing the detected shape with a reference shape. 17) A deviceas claimed in claim 13, wherein said given wavelength is a wavelength inthe ultraviolet range. 18) A device as claimed in claim 13, andcomprising an electromagnetic radiation source (31) for irradiating saidpigment of said given portion (15; 37). 19) A device as claimed in claim18, wherein the electromagnetic source (31) is designed to emitelectromagnetic radiation at a wavelength different from said givenwavelength of the electromagnetic radiation emitted by said pigment. 20)A packet having at least one given portion (15; 37) optically detectableat at least one given wavelength outside the visible range; the givenportion (15; 37) comprising at least one first line, and at least onesecond line crosswise to the first line; the first and second lineextending at least from a first edge (8, 9) to a second edge (8, 10) ofthe packet (2). 21) A packet having a given portion (15; 37) opticallydetectable at at least one given wavelength outside the visible range;the given portion (15; 37) comprising at least one first line (16), andat least one second line (17) crosswise to the first line (16); thefirst line (16) extending from a first edge (9) to a second edge (10) ofthe packet (2), and the second line (17) extending from a third edge (8)to a fourth edge (8) of the packet (2). 22) A packet as claimed in claim20, wherein the given portion (15; 37) comprises a grid (15) having afirst number of lines (16) parallel to one another, and a second numberof lines (17) parallel to one another and crosswise to the first numberof lines (16). 23) A packet as claimed in claim 20, wherein the givenportion (15; 37) extends at least partly along at least one edge (8; 9;10) of the packet (2). 24) A packet as claimed in claim 20, wherein thepacket (2) is formed from a blank (11); the given portion (15; 37)extending at least partly along at least part of the edge of the blank(11). 25) A packet as claimed in claim 20, wherein said given wavelengthis a wavelength in the ultraviolet range. 26) A blank for producing apacket (2) as claimed in claim 20, and comprising a given portion (15;37) optically detectable at at least one given wavelength outside thevisible range; the given portion (15; 37) comprising at least one firstline, and at least one second line crosswise to the first line; thefirst and second line each extending at least from a first edge (8; 9)to a second edge (8; 10) of the packet (2). 27) A blank for producing apacket (2) as claimed in claim 20, and comprising a given portion (15;37) optically detectable at at least one given wavelength outside thevisible range; the given portion (15; 37) comprising at least one firstline (16), and at least one second line (17) crosswise to the first line(16); the first line (16) extending from a first edge (9) to a secondedge (10) of the packet (2), and the second line (17) extending from athird edge (8) to a fourth edge (8) of the packet (2). 28) A blank asclaimed in claim 26, wherein the given portion (15) comprises a grid(15) having a first number of lines (16) parallel to one another, and asecond number of lines (17) parallel to one another and crosswise to thefirst number of lines (16). 29) A blank as claimed in claim 26, whereinthe given portion (15; 37) extends at least partly along at least onefold line (14) of the blank (11). 30) A blank as claimed in claim 26,wherein the given portion (15; 37) extends at least partly along atleast part of the edge of the blank (11).